... but kudos to you for trying! We know it's not easy. And it's not supposed to be. In order to get an episode 100% completed, you need to:
Win all levels
Get a gold time on all levels
Collect the card in all levels
... find the things we hid for you in the overworld 👀
Remember that you don't need 100% to progress to the next episode. For that, you just need your bear friend.
Special case: If you know you used to have 100% on Episode 1 and now suddenly you're down to 98%, here's how you fix that:
Go into Episode 1
Find the trampoline level (it's the last one on the line following the "Just jump" row of levels)
Complete that level again - you need to get a gold time and the card (even if you have done this previously).
You should now be back up to 100%.